Numerical analysis of air flow past the 2415-3S airfoil for an unmanned aerial vehicle with internal propulsion system

This paper deals with the prediction of pressure and velocity fields on the 2415-3S airfoil which will be used for and unmanned aerial vehicle with internal propulsion system and in this way analyze the air flow through an internal duct of the airfoil using computational fluid dynamics. The main objective is to evaluate the effect of the internal air flow past the airfoil and how this affects the aerodynamic performance by means of lift and drag forces. For this purpose, three different designs of the internal duct were studied; starting from the base 2415-3S airfoil developed in previous investigation, basing on the hypothesis of decreasing the flow separation produced when the propulsive airflow merges the external flow, and in this way obtaining the best configuration. For that purpose, an exhaustive study of the mesh sensitivity was performed. It was used a non-structured mesh since the computational domain is tridimensional and complex. The selected mesh contains approximately 12.5 million elements. Both the computational domain and the numerical solution were made with commercial CAD and CFD software respectively. Air, incompressible and steady was analyzed. The boundary conditions are in concordance with experimental setup in the AF 6109 wind tunnel. The k-ε model is utilized to describe the turbulent flow process as followed in references. Results allowed obtaining pressure and velocity contours as well as lift and drag coefficients and also the location of separation and reattachment regions in some cases for zero degrees of angle of attack on the internal and external surfaces of the airfoil. Finally, the selection of the configuration with the best aerodynamic performance was made, selecting the option without curved baffles

Analysis of air flow past and through the 2415-3S airfoil for an unmanned aerial vehicle with internal propulsion system

This paper deals with the prediction of velocity fields on the 2415-3S airfoil which will be used for an unmanned aerial vehicle with internal propulsion system and in this way analyze the air flow through an internal duct of the airfoil using computational fluid dynamics. The main objective is to evaluate the effect of the internal air flow past the airfoil and how this affects the aerodynamic performance by means of lift and drag forces. For this purpose, three different designs of the internal duct were studied; starting from the base 2415-3S airfoil developed in previous investigation, basing on the hypothesis of decreasing the flow separation produced when the propulsive airflow merges the external flow, and in this way obtaining the best configuration. For that purpose, an exhaustive study of the mesh sensitivity was performed. It was used a non-structured mesh since the computational domain is three-dimensional and complex. The selected mesh contains approximately 12.5 million elements. Both the computational domain and the numerical solution were made with commercial CAD and CFD software, respectively. Air, incompressible and steady was analyzed. The boundary conditions are in concordance with experimental setup in the AF 6109 wind tunnel. The k-e model is utilized to describe the turbulent flow process as followed in references. Results allowed obtaining velocity contours as well as lift and drag coefficients and also the location of separation and reattachment regions in some cases for zero degrees of angle of attack on the internal and external surfaces of the airfoil. Finally, the selection of the configuration with the best aerodynamic performance was made, selecting the option without curved baffles

Aeronautical Engineering: A special bibliography with indexes, supplement 69

This bibliography lists 305 reports, articles, and other documents introduced into the NASA scientific and technical information system in March 1976

CM Scale Flapping Wing Of Unmanned Aerial Vehicle At Very Low Reynolds Numbers Regime

This dissertation investigates the CM$-$SCALE Flapping Wing of Unmanned Aerial Vehicle (FWUAV) that can accommodate nacelles of the scale of current Unmanned Air vehicle (UAV) designs are complex systems and their utilization is still in its infancy. The improving design of unmanned aerial vehicle from previous teams by improving the wings and outer body of bird. So, to potentially improve wing design, a complaint joint mechanism is proposed in order to make wing flapping and provide lift and thrust needed to fly. Also, change the wing design from flat wing to airplane wing by using two different airfoils, NACA 0012 and s1223. For bird\u27s body change the internal body to ensure to contain all internal components and give more space for flapping wings. Concurrently a redesign of the outer shell by making it smoother and lighter will be commensurate with the updated design. In addition, development of an evaluation methodology for the capability of a flapping wing to replication design loads by using computational fluid dynamic CFD by using fluid structure interaction in 2D and 3D analysis. We will investigate the design and analysis of the flapping wing. Specifically, this includes: 1. Review of cm−Scale Unmanned Aerial Vehicle Model and design (a) Investigate flapping Mechanism. (b) Investigate gear mechanism 2. Analysis of flapping wings for MAV (a) Select Airfoils for flapping wing. (b) Analyze Flapping Wings. (c) Make recommendations for Tail design for MAV. (d) Make recommendations for the improved design of MAV body. 3. Development of Finite Element flapping wing Model. (a) 2D computational analysis for Airfoils. i. NACA0012 Airfoil. ii. s1223 Airfoil. (b) 3D computational analysis with different shape of wings. i. Relationship between critical parameters and performance. ii. Design Optimization. Which is new key to make flapping wing close to the nature or real flapping wing, a new wing design inspired from nature exactly from thrush and scaled to our design. Starting from gear design by choose proper gear system. Then redesign the wings to commensurate with new bird. Computational fluid analysis also will used to replicate the loads needed to fly. This is another important area in which the literature is not offering guidance. Addresses the lack of an overview paper in the literature that outlines the challenges of testing a full$-$scale flapping wing Unmanned aerial vehicle onto laminar flow test and suggests research direction to address these challenges. Although conceptual in nature, this contribution is expected to be significant given that it takes experience in the unmanned vehicle industry to determine what challenges matter and need to be addressed. The growth in testing full-scale unmanned air vehicle using a laminar flow test being recent limits the number of people who can offer the perspective needed to suggest a research roadmap

Review on Progress and Application of Active Flow Control Devices - Coandă Effect on Unmanned Aerial Vehicles

Coandă effect can be found in virtually all aerodynamic applications, and has drawn renewed interest for various applications, among others for generating lift and maneuvering impulses to be applied for unmanned air vehicles (UAV) and micro air vehicles (MAV). These air vehicles have the potential to revolutionize our sensing and information gathering capabilities, in homeland security and environmental areas. Sophisticated unmanned air vehicles for general applications have been developed rapidly across many different industries and interested researchers. In order to carry out a task, these air vehicles have to face many different challenges, due to the MAVs small size, flight regime, and modes of operation. This has led to the development of novel platforms that move away from traditional aircraft design in order to make them more capable. A good example is the Coandă MAV which uses the Active flow control–Coandă Effect. Improved aerodynamic performance of these air vehicles can lead to fast take off and slower landing speeds that can be related to reduce noise and crash survivability issues. The investigation and research in this field is rapidly rising and there are many concepts currently being considered around the world. This report provides an overview on the state of unmanned air vehicle and introduces the techniques of Active Flow Control ACF that could be potentially used for control of UAV. Furthermore, this paper may also focuses on the review research involved with the design modification and the generated flow phenomena of Micro air vehicle MAV

Innovative Propulsion Systems and CFD Simulation for Fixed Wings UAVs

Nowadays, mobile applications demand, in large extent, an improvement in the overall efficiency of systems, in order to diversify the number of applications. For unmanned aerial vehicles (UAVs), an enhancement in their performance translates into larger payloads and range. These factors encourage the search for novel propulsion architectures, which present high synergy with the airframe and remaining components and subsystems, to enable a better UAV performance. In this context, technologies broadly examined are distributed propulsion (DP), thrust split (TS), and boundary layer ingestion (BLI), which have shown potential opportunities to achieve ambitious performance targets (ACARE 2020, NASA N+3). The present work briefly describes these technologies and shows preliminary results for a conceptual propulsion configuration using a set number of propulsors. Furthermore, the simulation process for a blended wing body (BWB) airframe using computational fluid dynamics (CFD) OpenFOAM software is described. The latter is examined due to its advantages in terms of versatility and cost, compared with licensed CFD software. This work does not intend to give a broad explanation of each of the topics, but rather to give an insight into the state of the art in modeling of distributed propulsion systems and CFD simulation using open-source software implemented in UAVs

DESIGN OF A PROTOTYPE UNMANNED LIGHTER-THAN-AIR PLATFORM FOR REMOTE SENSING: CONTROL, ALIMENTATION, AND PROPULSION SYSTEMS

This work presents several aspects related to the design of a new concept for a Remotely Piloted Aircraft System (RPAS), specifically, a Lighter-Than-Air (LTA) platform for the remote sensing of medium-sized rural and urban areas. The airship’s payload is intended to carry an array of sensors ranging from high-definition video cameras to hyperspectral sensors, a thermographic camera, and a LiDAR system, which all require power alimentation during low-speed surveying for fine mapping. Here, a fuel cell design solution, combined with supercapacitors, is proposed. The system is designed to provide energy for both the onboard sensors and the propulsion and thrust vector control system. In this regard, the design and optimization of the propeller blades, using Blade Element Momentum Theory (BEMT), is discussed as well, in a multidisciplinary optimisation fashion. A twin paper describes the other structural aspects of the airship design

Architecture and Information Requirements to Assess and Predict Flight Safety Risks During Highly Autonomous Urban Flight Operations

As aviation adopts new and increasingly complex operational paradigms, vehicle types, and technologies to broaden airspace capability and efficiency, maintaining a safe system will require recognition and timely mitigation of new safety issues as they emerge and before significant consequences occur. A shift toward a more predictive risk mitigation capability becomes critical to meet this challenge. In-time safety assurance comprises monitoring, assessment, and mitigation functions that proactively reduce risk in complex operational environments where the interplay of hazards may not be known (and therefore not accounted for) during design. These functions can also help to understand and predict emergent effects caused by the increased use of automation or autonomous functions that may exhibit unexpected non-deterministic behaviors. The envisioned monitoring and assessment functions can look for precursors, anomalies, and trends (PATs) by applying model-based and data-driven methods. Outputs would then drive downstream mitigation(s) if needed to reduce risk. These mitigations may be accomplished using traditional design revision processes or via operational (and sometimes automated) mechanisms. The latter refers to the in-time aspect of the system concept. This report comprises architecture and information requirements and considerations toward enabling such a capability within the domain of low altitude highly autonomous urban flight operations. This domain may span, for example, public-use surveillance missions flown by small unmanned aircraft (e.g., infrastructure inspection, facility management, emergency response, law enforcement, and/or security) to transportation missions flown by larger aircraft that may carry passengers or deliver products. Caveat: Any stated requirements in this report should be considered initial requirements that are intended to drive research and development (R&D). These initial requirements are likely to evolve based on R&D findings, refinement of operational concepts, industry advances, and new industry or regulatory policies or standards related to safety assurance

Development of an Unmanned Aerial Vehicle for Atmospheric Turbulence Measurement

An unmanned aerial vehicle was developed to study turbulence in the atmospheric boundary layer. The development of the aircraft, BLUECAT5, and instrumentation package culminated in a series of flight experiments conducted in two different locations near Stillwater, Oklahoma, USA. The flight experiments employed the use of two of the unmanned aerial vehicles flying simultaneously, each containing a five-hole pressure probe as part of a turbulence-measuring instrumentation package. A total of 18 flights were completed with the objective to measure atmospheric properties at five altitudes between 20 and 120 meters. Multiple flights were flown over two days in which the effects of the diurnal cycle on the boundary layer were investigated. Profiles for mean wind velocity, temperature, and humidity all follow expected boundary layer behavior throughout the day. Evolution of the boundary layer can be seen with the early morning, stable boundary layer identified and its transition to the early mid-day convective mixed boundary layer observed. The corresponding increase in turbulence intensity was found to be significant. The success of the test campaign demonstrated the ability of the developed unmanned system to measure turbulence in the atmospheric boundary layer

Aeronautical engineering: A continuing bibliography with indexes (supplement 309)

This bibliography lists 212 reports, articles, and other documents introduced into the NASA scientific and technical information system in Oct. 1994. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment, and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics